Rotary regenerative heat exchangers comprising sealing devices having annular sealing plates

ABSTRACT

In a rotary regenerative heat exchanger of the type in which exhaust gas passage openings and compressed air passage openings are sealed against each other by annular sealing plates respectively provided along the edges of said openings and urged against the side wall of a rotating matrix rotor in sliding engagement therewith, a projecting portion is formed on one side of the sealing plate projecting toward the exhaust gas passage side or compressed air passage side to receive the pressure of the exhaust gas or compressed air on the surface thereof, or an arcuate groove is formed in the engaging surface of the annular sealing plate along the outer peripheral portion of said rotor to receive the compressed air therein, whereby said sealing plate is pressed against said rotor with predetermined pressure distribution over the entire length thereof and a loss due to leakage and wear of the engaging surfaces of said sealing plate and said rotor are prevented.

United States Patent [191 Fujikake et al.

[ 1 ROTARY REGENERATIVE HEAT EXCHANGERS COMPRISING SEALING DEVICES HAVING ANNULAR SEALING PLATES [75] Inventors: Kenji Fujikake; Masao Kitano;

Tsubura Nishiyama, all of Nagoya; Hisashi Sugimoto, Aichi, all of Japan [73] Assignee: Kabushiki Kaisha Toyota Chuo Kenkyusho, Nagoyo, Japan [22] Filed: Dec. 28, 1971 [21] Appl. No.: 213,007

[4 1 July 8,1975

Primary Examiner-Albert W. Davis, Jr. Attorney, Agent, or FirmCushman, Darby & Cushman 1 1 ABSTRACT In a rotary regenerative heat exchanger of the type in which exhaust gas passage openings and compressed air passage openings are sealed against each other by annular sealing plates respectively provided along the edges of said openings and urged against the side wall of a rotating matrix rotor in sliding engagement therewith, a projecting portion is formed on one side of the sealing plate projecting toward the exhaust gas passage side or compressed air passage side to receive the pressure of the exhaust gas or compressed air on the surface thereof, or an arcuate groove is formed in the engaging surface of the annular sealing plate along the outer peripheral portion of said rotor to receive the compressed air therein, whereby said sealing plate is pressed against said rotor with predetermined pressure distribution over the entire length thereof and a loss due to leakage and wear of the engaging surfaces of said sealing plate and said rotor are prevented.

9 Claims, 13 Drawing Figures SHEET FIG: 3

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SHEET a fig INLIFNTORS BY W ATTORNEYS ROTARY REGENERATIVE HEAT EXCHANGERS COMPRISING SEALING DEVICES HAVING ANNULAR SEALING PLATES FIELD OF INVENTION This invention relates to improvements in the sealing device used in rotary regenerative heat exchangers (hereinafter referred to simply as heat exchanger) for small-sized gas turbines, such as gas turbines for automobiles, for sealably separating a low pressure, high temperature exhaust gas passage and a high pressure, low temperature compressed air passage from each other.

BACKGROUND OF THE INVENTION Heat exchangers of the type described comprise sealing means for maintaining sealing between a stationary casing and a cylindrical rotor rotating in said casing. One of such sealing means heretofore used consists of first and second sealing devices respectively arranged along the peripheral edges of the low pressure, high temperature exhaust gas passage openings and the high pressure, low temperature compressed air passage opening, and each comprising a pressing member, such as a bellows or diaphragm, an annular flange member provided at one end of said pressing member and secured to the casing, and an annular sealing plate provided at the other end of said pressing member and slidably pressed against the side wall surface of the rotor.

In such sealing means, the sealing plate of the first or second sealing devices is held in sliding pressure contact with the side wall surface of the rotor under the resilient force of the bellows or diaphragm and fluid pressure, to achieve sealing between the casing and the rotor. Therefore, it is necessary to urge the sealing plate against the rotor surface with a greater force as the pressure differential between the exhaust gas and compressed air becomes greater during operation of the heat exchanger. There is the tendency that the force with which the sealing plate is urged against the rotor surface varies at portions of said sealing plate, i.e. it is excessively large at the portion where said sealing plate is in sliding contact with the portion of the rotor surface rotationally moving from the exhaust gas passage side toward the compressed air passage side, thus causing a premature wear of that portion of the sealing plate, while it is excessively small at the portion where said sealing plate is in sliding contact with the portion of the rotor surface rotationally moving from the compressed air passage side toward the exhaust gas passage side, thus resulting in an increasing amount of compressed air leaking into the exhaust gas passage through the gap formed between that portion of the sealing plate and the rotor surface. There is also the tendency that the sealing plate urging force becomes excessively large at the portion where said sealing plate is in sliding contact with the outer peripheral edge portion of the side surface of the rotor, resulting in an excessive wear of that portion of the sealing plate. With such tendencies, the sealing effect of the sealing device is extremely degraded and a satisfactory sealing cannot be obtained, which is a serious problem in the practical use of the heat exchangers.

SUMMARY OF THE INVENTION The present invention is intended to solve such problem The object of the present invention, therefore, is

to provide a heat exchanger comprising sealing devices having such an annular sealing plate (hereinafter referred to simply as sealing plate) which is capable of decreasing the loss due to leakage and the amount of wear of the sealing device to a minimum and thereby enabling a perfect sealing effect to be maintained.

To this end, the invention provides, for a rotary regenerative heat exchanger comprising:

a casing having means defining an exhaust gas inlet, an exhaust outlet, a compressed air inlet and a compressed air outlet;

a regenerative matrix rotor rotatably mounted in the casing, said rotor having two opposite faces with means defining an array of a plurality of fine passageways extending from one face to the opposite face of the rotor for alternately passing higher pressure compressed air and lower pressure exhaust gas as the rotor is rotated;

a first sealing device disposed between the casing and one face of the rotor perimetrically of the compressed air outlet for sealing between the casing and that one face of the rotor;

two second sealing devices, disposed between the casing and the respective two opposite faces of the rotor perimetrically of the exhaust gas inlet and outlet for sealing between the casing and the two opposite faces of the rotor;

each said sealing device including an annular flange secured to the casing, an annular resilient spring means secured to the flange and an annular sealing plate supported by the resilient spring means and slidably engaging a respective face of the rotor;

the improvement wherein:

the one of the second sealing devices which is disposed in engagement with the same face of the rotor as is engaged by the first sealing device,

a. is disposed adjacent the first sealing device,

b. has the sealing plate thereof including an arcuate portion which generally skirts the array of said plurality of fine passageways through the rotor and a remaining portion extending between opposite ends of the arcuate portion, the remaining porition traversing the array, so as to have a first segment which the fine passageways cross when rotatively proceeding from being positioned to pass exhaust gas toward being positioned to pass compressed air, and a second segment which the fine passageways cross when rotatively proceeding from being positioned to pass compressed air toward being positioned to pass exhaust gas, said first and second segments being serially adjacently disposed along said remaining portion;

c. the sealing plate of said one of the second sealing devices including a proximal face in sliding engagement with the rotor respective face and a distal face presented toward the spring means, with the thickness of the sealing plate extending between said proximal face and said distal face;

d. the last-mentioned sealing plate gradually changing in transverse corss-sectional shape along the perimetrical extent thereof, by at least one of:

. laterally inwardly projecting the first segment of the remaining portion of said one said second sealing device to provide a shoulder which faces the exhaust gas inlet, which shoulder substantially diminishes in lateral extent where said first and second segments adjoin one another and within said second segment;

2. relieving a laterally outward part of the proximal face of the first segment of the remaining portion of the one said second sealing device, to reduce the laterally outward extent of the proximal face relative to the effective outward lateral extent thereof where said first and second segments adjoin one another and within said second segment;

3. laterally outwardly projecting the second segment of the remaining portion of the one said second seling device to provide a shoulder portion of the proximal face of the second segment which shoulder substantially diminishes in lateral extent where said second and first segments adjoin one another and within said first segment; and

4. relieving a laterally innermost part of the second segment of the remaining portion of the one said second sealing device, to reduce the laterally inward extent of the proximal face relative to the effective inward lateral extent thereof where said second and first segments adjoin one another and within said first segment.

The foregoing and other objects, aspects and features of the invention will be apparent from a consideration of the following description and accompanying drawings, wherein:

FIG. 1 is an enlarged sectional view of the essential portion of a conventional rotary regenerative heat exchanger;

FIG. 2 is an illustrative view showing one mode of pressure change occurring on the annular sealing plate in the conventional heat exchanger;

FIG. 3 is a vertical sectional view of an embodiment of the rotary regenerative heat exchanger according to the present invention;

FIG. 4 is a transverse sectional view taken along the line IVIV of FIG. 3;

FIG. 5 is a plan view of the sealing device in the heat exchanger shown in FIG. 3;

FIGS. 6 to 8 are enlarged sectional views of the essential portion of the sealing device taken along the lines VI-VI, VIIVII and VIIIVIII ofFIG. 5 respectively;

FIG. 9 is a plan view of a sealing device in another embodiment of the present invention; and

FIGS. 10 to 13 are enlarged sectional views of the essential portion of the sealing device taken along the lines X--X, XI-XI, XII-XII and XIIIXIII of FIG. 9 respectively.

DETAILED DESCRIPTION OF PRESENTLY PREFERRED EMBODIMENTS Referring to FIGS. 3 to 13, there is shown a rotary regenerative heat exchanger E for gas turbines according to the present invention which comprises a compressed air sealing device A having a sealing plate la (hereinafter referred to as first sealing device) and an exhaust gas sealing device B having at least one sealing plate lb (hereinafter referred to as second sealing device). The heat exchanger E is composed of a casing 6 having exhaust gas passage openings 2 and 3 and compressed air passage openings 4 and 5, and a cylindrical rotor 8 rotatably mounted in said casing 6 and having a matrix 7 defining fine passages.

The rotor 8 is provided with a ring gear 10 centrally of the outer peripheral surface thereof, which is meshing with a pinion gear 12 fixedly mounted on a driving shaft 11. It will be understood that, by rotating the driving shaft 11 from a driving source (not shown), the rotor 8 is rotated within the casing 6.

The first sealing device A includes a diaphragm 13 disposed along the edge of the compressed air passage opening 5 formed in a side wall of the casing 6 and a flange 1 provided at one end thereof which is secured to the casing 6 by means of fittings 19 such as bolts and nuts, and the sealing plate la provided at the other end thereof and being slidably pressed against a side wall surface 14 of the rotor 8 in sealing engagement therewithv The second sealing device B, as shown in FIGS. 6 through 8 in an enlarged scale, includes a bellows 15 having an annular flange I at one end thereof which is secured to the casing 6 at its outer peripheral edge portion 17 by means of fittings 19, and the annular sealing plate lb provided at the other end 20 thereof and having a sliding surface 21 lightly slidably pressed against the side wall surface I4 of the rotor 8. The high pressure, low temperature compressed air from a compressor (not shown) is partially introduced into the interior of the bellows 15, whereby the sliding surface 21 of the sealing plate lb is urged more effectively against the side wall surface 14 of the rotor.

The bellows 15 of the sealing device B is made from a thin sheet of stainless steel or the like, and the sliding surface 21 of the sealing plate lb is coated with a ceramic film or the like to provide smooth frictional engagement wih the side wall surface 14 of the rotor 8 and minimize the wear. In the operation of the heat exchanger E, as shown in FIGS. 3 and 4, compressed air flows from the compressed air passage opening 4 into an annular chamber 22 defined by the outer peripheral surface 14a, the first sealing device A, the second sealing device B and the side wall 60 of the casing 6, and discharged from the compressed air passage opening 5 through the matrix 7 in the rotor 8 as indicated by the solid line arrow H, while high temperature exhaust gas flows into the heat exchanger from the exhaust gas inlet opening 2 and passes through the matrix 7 in the rotor, as indicated by the broken line arrow I, to be discharged from the exhaust gas outlet opening 3.

By the way, a conventional heat exchanger of the type described above has the disadvantage which will be described hereunder. As an example, a detailed explanation will be given with reference to a sealing device B corresponding to the sealing device B and shown in FIG. I. In the explanation, some of the reference numerals are quoted from those used in FIGS. 3 and 4. Namely, in the conventional heat exchanger a sealing plate lb, corrresponding to the sealing plate lb described above, has the same sectional shape at the portion 21a (FIG. 4) where said sealing plate is in sliding contact with the portion of the side wall surface 14 of the rotor 8 rotationally moving from the low pressure exhaust gas passage side 7b to the compressed air passage side 7a as indicated by the arrow K and at the portion 21b which is in sliding contact with the portion of the side wall surface I4 of the rotor 8 rotationally moving from the compressed air passage side 7a to the exhaust gas passage side 7b. With such construction, the high pressure, low temperature compressed air tends to leak from the compressed air passage side 7a to the low pressure, high temperature exhaust gas passage side 7b through the slight gap between the engaging surfaces of the sealing plate lb and the rotor 8 at the portion 21a. The compressed air leaking direction is opposite to the rotating direction of the rotor 8 as indicated by the arrows K in FIG. 4. These facts, together with the coefficient of viscosity of the compressed air, the peripheral speed of the rotor and the number of passages in the matrix in the rotor, bring about the phenomenon in which the pressure distribution between the engaging surfaces of the sealing plate and the rotor decreases relatively sharply at the portion 21a from the compressed air passage side 70 toward the exhaust gas passage side 7b. So the pressing force acting from the sealing plate lb to the side wall surface 14 of the matrix rotor 8 by the compressed air pressure in a bellows l5 and the resilient force of said bellows 15 is so large as to cause a heavy wear of said sealing plate 1b and destroy said side wall surface of said matrix rotor 8.

At the portion 21b of the sealing plate lb, on the other hand, the compressed air tends to leak from the compressed air passage side 70 to the exhaust gas passage side 7b through the slight gap between the engaging surfaces of said sealing plate lb and the rotor 8. The compressed air leaking direction is idential to the rotating direction of the rotor 8. These facts, together with the factors mentioned above, bring about the phenomenon in which the pressure distribution between the engaging surfaces of the sealing plate and the rotor decreases gently from the compressed air passage side 70 toward the exhaust gas passage side 7b at the portion 21b. So the pressing force acting from the sealing plate lb to the matrix rotor 8 by the compressed air pressure in said bellows l5 and the resilient force of said bellows 15 is so small as to allow the compressed air to leak, through the gap between the engaging surfaces of the sealing plate lb and the matrix rotor 8, from the compressed air passage side toward the exhaust gas passage side and as a result to reduce a sealing effect of the sealing device. The above-described phenomena tend to become more apparent as the rotating speed of the rotor increases, and the pressure differential tends to become greater from the central portion toward the peripheral edge 14a of the rotor 8.

The pressure leaking at the portions 21a and 21b acts to lift the sealing plate lb from the side wall surface l4 of the rotor. The compressed air pressure acting on the sealing plate lb to hold the latter in pressure contact with the side wall surface 14 of the rotor is equal at the portions 21a and 21b as said portions are identical in cross sectional shape. However, because of the abovedescribed difference between the pressure acting on the sliding surface of the sealing plate lb at the portion 21a and the pressure acting on the sliding surface of the sealing plate lb at the portion 21b, the pressure urging the sealing plate 1b against the side wall surface 14 of the rotor tends to become too large at the portion 21a, causing a heavy wear of the sealing plate at said portion, while the pressure urging said sealing plate lb against the side wall surface 14 of the rotor tends to become too small at the portion 21b, allowing a more compressed air to leak through the gap between the engaging surfaces of the sealing plate lb and the rotor 8. It has been confirmed through the repeated experiments and analyses that these tendencies are more apparent from the center toward the outer peripheral edge 14a of the rotor.

Further, in the sealing device B of the conventional heat exchanger the sealing plate lb has the same sectional shape at the portion 21c which is in sliding contact with the peripheral solid edge portion 14a of the rotor, and at the portions 210 and 21b described above. With such construction, the compressed air in the casing 6 tends to leak from the annular chamber 22 into the exhaust gas passage 7b through the slight gap between the engaging surfaces of the sealing plate lb and the rotor 8 at the portion 21c. This, together with the coefficient of viscosity of the compressed air, bring about the phenomenon that the pressure distribution between the engaging surfaces of the sealing plate and the rotor decreases considerably sharply at the portion 2lc from the annular compressed air chamber 22 toward the exhaust gas passage 7b as indicated by the solid curve a in FIG. 2. It has also been confirmed through the repeated experiments and analyses that the sealing plate lb is pressed with an excessively large pressure against the peripheral solid edge portion [4a of the rotor at the portion 210 and worn out rapidly at said portion.

The present inventors conducted a study with a view to eliminating the above-described disadvantages of the sealing device of the conventional heat exchanger and, as a result, arrived at the claimed heat exchanger comprising improved sealing devices. For the sake of convenience, the present invention will be described on the exhaust gas sealing device or the second sealing device. The present invention has two aspects according to the places to be sealed.

According to one aspect of the invention, there is provided a rotary regenerative heat exchanger comprising a casing having exhaust gas passage openings and compressed air passage openings, a regenerative matrix rotor rotatably mounted in said casing, and first and second sealing device provided annularly along the peripheral edges of one of said compressed air passage openings and said exhaust gas passage openings respectively and each being secured to said casing at one end and having at the other end a sealing plate slidably engaging the side wall surface of said rotor under pressure, wherein the sealing plate of that one of said sealing devices which has a relatively large pressure differential between the interior and exterior thereof, has different sectional shapes at the portion where said sealing plate is in sliding contact with the portion of the side wall surface of said rotor rotationally moving from the exhaust gas passage side toward the compressed air passage side, and at the portion where said sealing plate is in sliding contact with the portion of the side wall surface of said rotor rotationally moving from the compressed air passage side toward the exhaust gas passage side.

The substantial structural difference between the heat exchanger according to the first aspect of the invention and the conventional one lies in the fact that the sealing plate of that one of the sealing devices which has a relatively large pressure differential between the interior and exterior thereof is formed with a first projecting portion radially inwardly projecting from the lower portion of the inner peripheral surface thereof toward the exhaust gas passage for sliding contact with the rotor, at the portion where said sealing plate is in sliding contact with the portion of the side wall surface of the rotor rotationally moving from the exhaust gas passage side toward the compressed air passage side, and is formed with a second projecting portion radially outwardly projecting from the lower portion of the outer peripheral surface thereof toward the compressed air passage, at the portion where said sealing plate is in sliding contact with the side wall surface of the rotor rotationally moving from the compressed air passage side toward the exhaust gas passage side. Because of such structural difference as above described, the sealing plate is pressed against the side wall surface of the rotor with an optimum pressure distribution at every portion thereof, so that the sealing effect of the sealing device can be enhanced, the wear of the sealing plate can be prevented which has been encountered in the conventional sealing device due to excessive pressure applied thereto, and further a loss of compressed air due to leakage otherwise occurring through the gap between the engaging surfaces of the sealing plate and the rotor can be avoided. Therefore, the heat exchanger comprising such sealing device as described above is more effective and advantageous than the conventional heat exchanger comprising the sealing device having the sealing plate of the type described previ ously.

FIGS. through 7 show, in an enlarged scale, the sealing device used in the heat exchanger according to the first aspect of the invention, in which same parts as those in FIGS. 3 and 4 are indicated by same reference numerals.

A substantially annular, D-shaped sealing device 8., as shown in FIGS. 5 through 8, includes a bellows having a height of 6 mm and made, for example, from a 0.05 mm thick stainless steel sheet by rolling and bending, an annular flanged member 1 connected to one end 16 of said bellows l5 and secured to the casing 6 at a flange 17 by means of fittings 19 such as bolts and nuts, and an annular sealing plate lb connected to the other end 20 of said bellows l5 and having a sliding surface 21 which is slidably pressed against the side wall surface 14 of the rotor 8. At the portion 21a of the sealing plate lb where said sealing plate is in sliding contact with the portion of the side wall surface 14 of the rotor 8 rotationally moving from the exhaust gas passage side 7b toward the compressed air passage side 7a, the high pressure, low temperature compressed air tends to leak into the low pressure, high temperature exhaust gas passage side 7b through the slight gap between the engaging surfaces of the sealing plate and the rotor and, because of this tendency and the fact that the rotating direction of the rotor 8 is opposite to the compressed air leaking direction, the compressed air pressure decreases relatively sharply from the compressed air passage side 7a toward the exhaust gas passage side 7b and the sealing plate is pressed against the rotor with excessively large force at said portion 21a. In order to avoid such disadvantages, the sealing plate lb of the sealing device B in the heat exchanger of this invention is formed, at the portion 21a, with a first projecting portion 230 projecting radially inwardly from the lower portion of the inner peripheral surface thereof toward the exhaust gas passage side 7b, so as to receive the low exhaust gas pressure on the upper surface 24a of said first projecting portion 23a, and also with a recess 25a extending radially inwardly from the lower portion of the outer peripheral surface thereof, so as to receive the high compressed air pressure on the upper surface 26a of said recess 25a to cancel the compressed air pressure applied on that part of the end of said bellows which corresponds to said upper surface 26a of the recess 25a, thereby to eliminate the excess pressing force acting from the sealing plate lb to the side wall surface 14 of said matrix rotor 8 and prevent destroying the side wall surface 14 of said matrix rotor 8.

At the portion Zlb of the sealing plate lb where said sealing plate is in sliding contact with the portion of the side wall surface 14 of the rotor 8 rotationally moving from the compressed air passage side 7a toward the exhaust gas passage side 7b the high pressure, low temperature compressed air tends to leak from the compressed air passage side 7a toward the low pressure, high temperature exhaust gas passage side 7b through the slight gap between the engaging surfaces of the sealing plate and the rotor. This tendency plus the fact that the rotating direction of the rotor 8 is identical to the compressed air leaking direction, causes the compressed air pressure to decrease gently from the compressed air passage side 7a toward the exhaust gas passage side 7b, with the result that the sealing plate is pressed against the rotor with insufficient force. In order to overcome such disadvantage, the sealing plate lb in the present invention, as shown in FIGS. 5 and 7, is formed at the portion 21b with a second projecting portion 23b projecting radially outwardly from the lower portion of the outer peripheral surface thereof toward the compressed air passage side so as to receive the high compressed air pressure on the upper surface 24b of said second projecting portion 23b, and also with a recess 25b extending radially outwardly from the lower portion of the inner peripheral surface thereof so as to receive the low exhaust gas pressure on the upper surface 26b of said recess 25b, so that the compressed air pressure acts on said second projecting portion 23b to supplement the insufficient pressing force acting from sealing plate lb to the side wall sur face 14 of the matrix rotor 8 and to prevent leakage of the compressed air pressure from the compressed air passage side toward the exhaust gas passage side.

in the sealing device B shown in FIGS. 5 through 7, as described above, the sealing plate lb is provided with the first projecting portion 23a and the recess 25a, respectively having the pressure receiving surfaces 240 and 26a, at the portion Zla where said sealing plate is in sliding contact with the portion of the rotor surface rotationally moving from the exhaust gas passage side 7b toward the compressed air passage side 7a, and is provided with the second projecting portion 23b and the recess 25b, respectively having the pressure receiving surfaces 24b and 26b, at the portion 21b where said sealing plate is in sliding contact with the portion of the rotor surface rotationally moving from the compressed air passage side 7a toward the exhaust gas passage side 7b, so that the compressed air pressure or exhaust gas pressure may be applied to said pressure receiving surfaces. Therefore, the distribution of the pressure urging said sealing plate into sliding contact with the rotor surface I4 is controlled at the portions 210 and 21b and the sealing plate is pressed against the rotor with an optimum pressure. This is advantageous in preventing a wear of the engaging surfaces of the sealing plate and the rotor and hence preventing a leakage of the pressurized fluid.

According to the second aspect of the invention, there is provided a rotary regenerative heat exchanger comprising a casing having exhaust gas passage opening and compressed air passage openings, a regenerative matrix rotor rotatably mounted in said casing, and first and second sealing devices provided annularly along the peripheral edges of one of said compressed air passage openings and said exhaust gas passage openings respectively and each being secured to said casing at one end and having at the other end a sealing plate slidably engaging the side wall surface of said rotor under pressure, wherein the sealing plate of that one of said sealing devices which has a relatively large pressure differential between the interior and exterior thereof, has in the sliding surface thereof a groove extending substantially centrally of the arcuate portion of said sliding surface and a plurality of radial slits communicating said groove with the exterior of said sealing device for introducing compressed air into said groove therethrough, said radial slits forming a projecting portion between each of said slits and a resilient spring means.

In the conventional sealing device B, the sealing plate lb has the same sectional shape at the portion 21(- which is in sliding contact with the peripheral edge portion 14a of the rotor. at the portion 21a where said sliding plate is in sliding contact with the portion of the rotor surface 14 rotationally moving from the exhaust gas passage side 7b toward the compressed air passage side 7a, and at the portion 21b where said sealing plate is in sliding contact with the portion of the rotor surface 14 rotationally moving from the compressed air passage side 7a toward the exhaust gas passage side 7b. as described previously with reference to FIGS. 1 through 4, and therefore, had the disadvantages also as described previously. The heat exchanger of the invention which will be described hereunder precludes a failure of the sealing device attributable to such disadvantages and is ensured of perfect sealing effect.

This heat exchanger comprises sealing devices B, which will be described with reference to FIGS. and 8 in which parts similar to those in FIGS. 3 and 4 are indicated by same reference numerals.

In the sealing device B the sealing plate lb has in the sliding surface thereof a groove 27 extending substantially along the center of the arcuate portion 21c and a plurality of radial slits 28 communicating said groove 27 with the exterior of the sealing device for introducing the compressed air from the chamber 22 into said groove therethrough, said groove having a depth extending at right angles to the sliding surface of the sealing plate, said radial slits forming a projecting portion between each of said slits and a bellows 15, whereby the compressed air pressure acts upwardly toward the lower surface of said projecting portion of the sealing plate to cancel the excess pressing force acting from the sealing plate to the solid side wall surface 14a of the rotor 8. As a result, a pressure distribution as indicated by the broken line in FIG. 2 is obtained on the sliding surface at the portion 210 and the sealing plate 1b is pressed against the solid side wall surface 14a of the rotor with the optimum pressure, and therefore, wear or seizure of the sealing plate Ib and the rotor can be prevented. The heat exchanger comprising such sealing device is highly advantageous.

Although, in the embodiments described above, the present invention has been described as applied to the type of heat exchanger in which the sealing plate is slidably pressed against the side wall of the rotor by making use of the resilient force of the bellows and fluid pressure, it should be understood that the invention is also similarly applicable to a type of heat exchanger in which the sealing plate is slidably pressed against the side wall of the rotor by making use of the resilient force of a diaphragm and fluid pressure. Such type of heat exchanger according to the invention will be described with reference to FIGS. 9 through 13 in which parts similar to those in FIGS. 3 th rough 8 are indicated by same reference numerals.

As shown in FIGS. 9 through 13, the sealing device B includes a diaphragm 15a consisting of a pair of annular plate members 16a and 16b, an annular flange member 1 fixed at its peripheral edge portion 17 to the casing 6 of the heat exchanger by means of fitting 19, an annular sealing plate 10!; having a sliding surface 2] in slidable pressure contact with the side wall surface 14 of the rotor 8 and an annular reinforcing member 31 supporting said disphragm 15a, said annular plate member 16a having the inner peripheral edge 30 integrally sealingly connected to said reinforcing member 31 by soldering and the outer peripheral edge integrally sealingly connected to the inner peripheral edge of said flange member I by soldering, and said annular plate member 16b having the inner peripheral edge integrally sealingly connected to said reinforcing member 31 by soldering and the outer peripheral edge integrally sealingly connected to an upright member 100 by soldering. In the conventional sealing device of the type described, the sealing plate 10b has the same sectional shape as indicated by numeral 21 in FIG. 10, at the portion 21a where said sealing plate is pressed against the portion of the side wall surface of the rotor 8 rotationally moving from the exhaust gas passage side 7b toward the compressed air passage side 7a, but in the present invention said portion of the sealing plate has a sectional shape as shown in FIG. I]. Namely, the sealing plate 10b at the portion 210 is composed of an upright member 100 and a first projecting portion 23c connected at the outer edge to the lower end of said upright member 100, the inner edge of said first projecting portion 230 projecting inwardly toward the exhaust gas passage side 7b and said first projecting portion 23c being progressively increased in width from the center toward the outer peripheral edge of the rotor 8, thereby to receive the exhaust gas pressure on the upper surface 24c of said first projecting portion 23c of the sealing plate 10b, eliminate the excess pressing force acting from sealing plate 10b to said matrix rotor 8 and prevent destroying the side wall surface 14 of said matrix rotor 8.

In the conventional sealing device, the sealing plate 10b has the same sectional shape as indicated by numeral 21 in FIG. 10, also at the portion 21b where said sealing plate is in sliding contact with the portion of the side wall surface 14 of the rotor rotationally moving from the compressed air passage side toward the exhaust gas passage side 7b. In the present invention, the sealing plate 10b at the portion 21b has a sectional shape as shown in FIG. 12. Namely, at the portion 21b the upright member la is erected from the inner peripheral edge portion of a second projecting portion 23d so as to receive the compressed air pressure on the upper surface 24d of said projecting portion 23d, thereby to supplement the insufficient pressing force applied to the sealing plate 10b with the compressed air pressure.

Further, in the conventional sealing device the sealing plate 10b has the same sectional shape as indicated by numeral 2] in FIG. 10, also at the portion 21c where said sealing plate is in sliding contact with the outer peripheral solid edge portion 140 of the side wall surface 14 of the rotor 8. In the present invention, said portion 216 of the sealing plate b has a sectional shape as shown in FIG. 13. Namely, the sliding surface of the sealing plate 10b is formed with a groove 27a extending substantially along the center of the arcuate portion 21c and having a depth at right angles to said sliding surface and a plurality of radial slits 28a communicating said groove 270 with the exterior of the sealing plate for introducing the high pressure compressed air into said groove 27a from the chamber 22 therethrough, said radial slits forming a projecting portion between each of said slits and said upright member 10c, whereby the compressed air pressure acts upwardly toward the lower surface of said projecting portion to cancel the excess pressing force acting from the sealing plate to the solid side wall surface 14a of the rotor 8.

Such construction of the sealing plate 10b as described above enables said sealing plate to be pressed against the side wall surface of the rotor 8 with the optimum pressure distribution over the entire length thereof, and thus the local wear of the engaging surfaces of the sealing plate and the rotor caused by unevenness in the pressure applied to the sealing plate and the loss of compressed air due to leakage can be avoided which have been encountered in the conventional heat exchanger. The heat exchanger comprising such sealing device, therefore, is of great practical advantage.

The sealing devices according to the present invention are classified into two types, one using a bellows and another using a diaphragm, and the sealing plates used in the respective types are not the same, as described above. These sealing plates can be used either selectively or concurrently in one heat exchanger according to the purpose of use of the heat exchanger.

It is also to be understood that, although the present invention has been described and illustrated herein in terms of specific embodiments thereof, many changes and modifications are possible to the details of the embodiments without deviating from the spirit of the invention set forth in the appended claims.

What is claimed is:

l. A rotary regenerative heat exchanger comprising:

a casing having exhaust gas passage openings and compressed air passage openings,

a regenerative matrix rotor rotatably mounted in said casing,

a first and second sealing devices disposed between said casing and said regenerative matrix rotor, said first sealing device being provided annularly along the peripheral edge of one of said compressed air passage openings, and said second sealing device being provided annularly along the peripheral edge of each of said exhaust gas passage openings, each of said first and second sealing devices comprising:

a flange secured to said casing,

a resilient spring means secured to said flange,

a sealing plate supported by said resilient spring means for slidably engaging the sidewall surface of said rotor, said sealing plate having an arcuate portion and remaining portion extending between opposite ends of said arcuate portion, said remaining portion being traversed by the rotational direction 6 of the rotor when it is rotated from one pressure side to the other pressure side, and said sealing plate of at least one of said first and second sealing devices that has large pressure differential between the interior and exterior thereof having a projecting portion formed integrally therewith, said projecting portion being projected from that portion of the sealing plate which is fixed to the resilient spring means toward the counter-direction of the rotation of the rotor, and said projecting portion being in direct contact with said one face of the rotor and being elongated continuously over a predetermined length from one end part of said arcuate portion to the middle portion of the length of said remaining portion of the sealing plate, with the width of said projecting portion being gradually varied, thereby to receive sufficient pressure on said projecting portion whereby the sealing plate is pressed against the side wall surface of the rotor with optimum pressure distribution over the entire length thereof. 2. A rotary regenerative heat exchanger according to claim I, wherein said sealing plate of the second sealing device provided annularly along the peripheral edge of said exhaust gas passage opening has a projecting portion formed integrally therewith and radially inwardly projecting from the inner peripheral surface of said sealing plate toward the exhaust gas passage at the area where said sealing plate is in sliding contact with said side wall surface of the rotor rotationally moving from the exhaust gas passage side toward the compressed air passage side, thereby to receive the exhaust gas pressure thereon and to control pressure distribution to said side wall surface on the rotor. 3. A rotary regenerative heat exchanger according to claim 1, wherein said sealing plate of the second sealing device provided annularly along the peripheral edge of said exhaust gas passage opening has a projecting portion formed integrally therewith and radially outwardly projecting from the outer peripheral surface of said sealing plate toward the compressed air passage at the area where said sealing plate is in sliding contact with said side wall surface of the rotor rotationally moving from the compressed air passage side toward the exhaust gas passage side, thereby to receive the compressed air pressure thereon and to control pressure distribution to said side wall surface of the rotor. 4. A rotary regenerative heat exchanger according to claim 2, wherein said sealing plate of the second sealing device has further a projecting portion formed integrally therewith and radially outwardly projecting from the outer peripheral surface of said sealing plate toward the compressed air passage at the area where said sealing plate is in sliding contact with said side wall surface of the rotor rotationally moving from the compressed air passage side toward the exhaust gas passage side, thereby to receive the compressed air pressure thereon and to control pressure distribution to said side wall surface of the rotor. 5. A rotary regenerative heat exchanger according to claim 2, wherein said sealing plate of the second sealing device has further a recess formed integrally therewith and radially inwardly extending from the lower portion of the outer peripheral surface thereof at the area where said sealing plate is in sliding contact with said side wall surface of the rotor rotationally moving from the exhaust gas passage side toward the compressed air passage side, thereby to receive the compressed air pressure thereon and to control pressure distribution to said side wall surface of the rotor.

6. A rotary regenerative heat exchanger according to claim 3, wherein said sealing plate of the second sealing device has further a recess formed integrally therewith and radially outwardly extending from the lower portion of the inner peripheral surface thereof at the area where said sealing plate is in sliding contact with said side wall surface of the rotor rotationally moving from the compressed air passage side toward the exhaust gas passage side, thereby to receive the exhaust gas pressure thereon and to control pressure distribution to said side wall surface of the rotor.

7. A rotary regenerative heat exchanger according to claim 5, wherein said sealing plate of the second sealing device has further a projecting portion formed integrally therewith and radially outwardly projecting from the outer peripheral surface of said sealing plate toward the compressed air passage, and a recess formed integrally therewith and radially outwardly extending from the lower portion of the inner peripheral surface thereof at the area where said sealing plate is in sliding contact with said side wall surface of the rotor rotationally moving from the compressed air passage side toward the exhaust gas passage side, thereby to receive the compressed air pressure and the exhaust gas pressure on said projecting portion and said recess and to control pressure distribution to said side wall surface of the rotor.

8. A rotary regenerative heat exchanger according to claim 7, wherein said resilient spring means is bellows means which is made from a thin sheet of stainless steel and is filled with compressed air, and said sliding surface of the sealing plate is coated with a ceramic film in order to provide smooth frictional engagement with the side wall surface of the rotor and minimize the wear.

9. A rotary regenerative heat exchanger according to claim 4, wherein said resilient spring means is a diaphragm spring and said sealing plate has un upright member fixed on the upper surface thereof for securing said sealing plate to said diaphragm. 

1. A rotary regenerative heat exchanger comprising: a casing having exhaust gas passage openings and compressed air passage openings, a reGenerative matrix rotor rotatably mounted in said casing, a first and second sealing devices disposed between said casing and said regenerative matrix rotor, said first sealing device being provided annularly along the peripheral edge of one of said compressed air passage openings, and said second sealing device being provided annularly along the peripheral edge of each of said exhaust gas passage openings, each of said first and second sealing devices comprising: a flange secured to said casing, a resilient spring means secured to said flange, a sealing plate supported by said resilient spring means for slidably engaging the sidewall surface of said rotor, said sealing plate having an arcuate portion and remaining portion extending between opposite ends of said arcuate portion, said remaining portion being traversed by the rotational direction of the rotor when it is rotated from one pressure side to the other pressure side, and said sealing plate of at least one of said first and second sealing devices that has large pressure differential between the interior and exterior thereof having a projecting portion formed integrally therewith, said projecting portion being projected from that portion of the sealing plate which is fixed to the resilient spring means toward the counter-direction of the rotation of the rotor, and said projecting portion being in direct contact with said one face of the rotor and being elongated continuously over a predetermined length from one end part of said arcuate portion to the middle portion of the length of said remaining portion of the sealing plate, with the width of said projecting portion being gradually varied, thereby to receive sufficient pressure on said projecting portion whereby the sealing plate is pressed against the side wall surface of the rotor with optimum pressure distribution over the entire length thereof.
 2. A rotary regenerative heat exchanger according to claim 1, wherein said sealing plate of the second sealing device provided annularly along the peripheral edge of said exhaust gas passage opening has a projecting portion formed integrally therewith and radially inwardly projecting from the inner peripheral surface of said sealing plate toward the exhaust gas passage at the area where said sealing plate is in sliding contact with said side wall surface of the rotor rotationally moving from the exhaust gas passage side toward the compressed air passage side, thereby to receive the exhaust gas pressure thereon and to control pressure distribution to said side wall surface on the rotor.
 3. A rotary regenerative heat exchanger according to claim 1, wherein said sealing plate of the second sealing device provided annularly along the peripheral edge of said exhaust gas passage opening has a projecting portion formed integrally therewith and radially outwardly projecting from the outer peripheral surface of said sealing plate toward the compressed air passage at the area where said sealing plate is in sliding contact with said side wall surface of the rotor rotationally moving from the compressed air passage side toward the exhaust gas passage side, thereby to receive the compressed air pressure thereon and to control pressure distribution to said side wall surface of the rotor.
 4. A rotary regenerative heat exchanger according to claim 2, wherein said sealing plate of the second sealing device has further a projecting portion formed integrally therewith and radially outwardly projecting from the outer peripheral surface of said sealing plate toward the compressed air passage at the area where said sealing plate is in sliding contact with said side wall surface of the rotor rotationally moving from the compressed air passage side toward the exhaust gas passage side, thereby to receive the compressed air pressure thereon and to control pressure distribution to said side wall surface of the rotor.
 5. A rotary regenerative heat exchanger according to claim 2, wherein Said sealing plate of the second sealing device has further a recess formed integrally therewith and radially inwardly extending from the lower portion of the outer peripheral surface thereof at the area where said sealing plate is in sliding contact with said side wall surface of the rotor rotationally moving from the exhaust gas passage side toward the compressed air passage side, thereby to receive the compressed air pressure thereon and to control pressure distribution to said side wall surface of the rotor.
 6. A rotary regenerative heat exchanger according to claim 3, wherein said sealing plate of the second sealing device has further a recess formed integrally therewith and radially outwardly extending from the lower portion of the inner peripheral surface thereof at the area where said sealing plate is in sliding contact with said side wall surface of the rotor rotationally moving from the compressed air passage side toward the exhaust gas passage side, thereby to receive the exhaust gas pressure thereon and to control pressure distribution to said side wall surface of the rotor.
 7. A rotary regenerative heat exchanger according to claim 5, wherein said sealing plate of the second sealing device has further a projecting portion formed integrally therewith and radially outwardly projecting from the outer peripheral surface of said sealing plate toward the compressed air passage, and a recess formed integrally therewith and radially outwardly extending from the lower portion of the inner peripheral surface thereof at the area where said sealing plate is in sliding contact with said side wall surface of the rotor rotationally moving from the compressed air passage side toward the exhaust gas passage side, thereby to receive the compressed air pressure and the exhaust gas pressure on said projecting portion and said recess and to control pressure distribution to said side wall surface of the rotor.
 8. A rotary regenerative heat exchanger according to claim 7, wherein said resilient spring means is bellows means which is made from a thin sheet of stainless steel and is filled with compressed air, and said sliding surface of the sealing plate is coated with a ceramic film in order to provide smooth frictional engagement with the side wall surface of the rotor and minimize the wear.
 9. A rotary regenerative heat exchanger according to claim 4, wherein said resilient spring means is a diaphragm spring and said sealing plate has un upright member fixed on the upper surface thereof for securing said sealing plate to said diaphragm. 